Analog-to-digital converter with a continuously calibrated voltage reference
US5319370A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1992 |
| Grant date | Jun 7, 1994 |
| Priority date | — |
| Expiry date | Aug 31, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R35/005
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for calibration of errors in the analog reference voltage input of an analog-to-digital converter. A monolithic reference voltage generator is provided to generate the analog reference which includes a bandgap voltage reference (50) that outputs an untrimmed voltage and a temperature voltage. The untrimmed voltage and temperature voltage are input to a delta-sigma A/D converter (52) which has the output thereof processed through a digital filter (54) to output data on a data bus (58) for storage in an EEPROM (60). The EEPROM (60) is operable in one mode to store temperature history data and, in another mode, to store temperature compensation data. In one mode, temperature compensation parameters are retrieved from the EEPROM (60) and utilized by a multiplier/accumulator circuit (74) to generate compensation factors which are output as a digital word to a DAC (76) for controlling a trim circuit (14). The trim circuit (14) provides a temperature compensation for the output of the bandgap voltage reference (50). The system is operable in a calibration mode to measure temperatures during a burn-in procedure and calculate necessary information to determine compens…
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